Killer whales of Sea Lion Island

Identification

Photo-identification

Identification of killer whales is mostly based on features of the saddle patch, the whitish area below the dorsal fin. Killer whales have scars and signs on the saddle patch that are often peculiar in shape, and permit identification. These scars are assumed to be quite stable during the lifetime, permitting long term recognition.

Saddle patch features of Nene, a young killer whale resident at Sea Lion Island

The identification by saddle patch scars can be augmented using the dorsal fin profile. In this case fin matching software, like DARWIN, may help in the identification process.

Identification using DARWIN dorsal fin matching software

Number of individuals

Using photo-identification we have been able to identify a total of 33 individuals, 42% of them resident at Sea Lion Island, i.e., regularly observed each breeding season, and in consecutive seasons.

Number of identifications of resident and transient killer whales

Resident killer whales

The presence of peculiar scars on the saddle patch permits identification in the long term. Some of the killer whales that are now resident at Sea Lion Island have been identified in pictures dating back to 2004. For example, Puma, a resident female killer whale, has been identified in pictures taken from 2004 to 2016.